Structural highlights
Function
IPNA_EMENI Isopenicillin N synthase; part of the gene cluster that mediates the biosynthesis of penicillin, the world's most important antibiotic (PubMed:3319778, PubMed:11755401). IpnA catalyzes the cyclization of the tripeptide N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine (LLD-ACV or ACV) to form isopenicillin N (IPN) that contains the beta-lactam nucleus (PubMed:3319778, PubMed:11755401, PubMed:28703303). The penicillin biosynthesis occurs via 3 enzymatic steps, the first corresponding to the production of the tripeptide N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine (LLD-ACV or ACV) by the NRPS acvA. The tripeptide ACV is then cyclized to isopenicillin N (IPN) by the isopenicillin N synthase ipnA that forms the beta-lactam nucleus. Finally, the alpha-aminoadipyl side chain is exchanged for phenylacetic acid by the isopenicillin N acyltransferase penDE to yield penicillin in the peroxisomal matrix (By similarity).[UniProtKB:P08703][1] [2] [3]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Isopenicillin N synthase (IPNS) is a non-haem iron oxidase that catalyses the formation of bicyclic isopenicillin N from delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV). In this study we report a novel activity for the iron of the IPNS active site, which behaves as a Lewis acid to catalyse the elimination of HF from the fluorinated substrate analogue, delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-beta-fluorovaline (ACbetaFV). X-Ray crystallographic studies of IPNS crystals grown anaerobically with ACbetaFV reveal that the valinyl beta-fluorine is missing from the active site region, and suggest the presence of the unsaturated tripeptide delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-isodehydrovaline in place of substrate ACbetaFV. (19)F NMR studies confirm the release of fluoride from ACbetaFV in the presence of the active IPNS enzyme. These results suggest a new mode of reactivity for the IPNS iron centre, a mechanism of action that has not previously been reported for any of the iron oxidase enzymes.
Active-site-mediated elimination of hydrogen fluoride from a fluorinated substrate analogue by isopenicillin N synthase.,Grummitt AR, Rutledge PJ, Clifton IJ, Baldwin JE Biochem J. 2004 Sep 1;382(Pt 2):659-66. PMID:15175003[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Ogle JM, Clifton IJ, Rutledge PJ, Elkins JM, Burzlaff NI, Adlington RM, Roach PL, Baldwin JE. Alternative oxidation by isopenicillin N synthase observed by X-ray diffraction. Chem Biol. 2001 Dec;8(12):1231-7. PMID:11755401
- ↑ McNeill LA, Brown TJN, Sami M, Clifton IJ, Burzlaff NI, Claridge TDW, Adlington RM, Baldwin JE, Rutledge PJ, Schofield CJ. Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non-Heme Iron Oxidases. Chemistry. 2017 Sep 18;23(52):12815-12824. doi: 10.1002/chem.201701592. Epub 2017, Aug 21. PMID:28703303 doi:http://dx.doi.org/10.1002/chem.201701592
- ↑ Ramon D, Carramolino L, Patino C, Sanchez F, Penalva MA. Cloning and characterization of the isopenicillin N synthetase gene mediating the formation of the beta-lactam ring in Aspergillus nidulans. Gene. 1987;57(2-3):171-81. doi: 10.1016/0378-1119(87)90120-x. PMID:3319778 doi:http://dx.doi.org/10.1016/0378-1119(87)90120-x
- ↑ Grummitt AR, Rutledge PJ, Clifton IJ, Baldwin JE. Active-site-mediated elimination of hydrogen fluoride from a fluorinated substrate analogue by isopenicillin N synthase. Biochem J. 2004 Sep 1;382(Pt 2):659-66. PMID:15175003 doi:10.1042/BJ20040529
